Hi
So the overall is a little too generic. Plus we do not write peoples work for them, unless we are getting paid as the consultants many of us are.
You have to do some searching and try to give it a shot :-0)
Here are some things though
1. You can definitely send bulk items to the requester so thats good for you
2. One issue you will have to overcome is, how does the Requester select the 20-25 items, as you cannot setup Power Automate to trigger that way. You can do things like Schedule flows to run every XXX times a day, and have it look for batches to create an approval for, otherwise you have to give the Requester a UI to select the ones to approve
3. Going to a single approver easy and updating the List after Approve/Reject is easy enough, you could even have a tracking table for responses etc.
However, now you added in what if you wanted to break up the items to many different approves. Now you are talking about how to do that.
1. Does it happen in Parallel, or is it step approvals. The requester has to be able to us a UI to trigger these.
Power Automate is only part of the solution, but it will do part of it and the bigger pieces
Cheers and good luck